How do I setup a delay before new instances are launched?

Details

Description

By default new ec2 instances are launched when not enough nodes are available to process jobs in the build queue. This is working great for us.

The question I have is if there is a way to have a job wait in the build queue for a defined period of time before a new instance is launched?

The reason I am asking is there are many times a job will finish on an existing instance and if we had just had a wait of 60 seconds we could have saved launching a new instance which would run until the idle timeout occurs.